Cahita sucker

Where they come from

Cahita suckers are river fish from northwestern Mexico. Think clear to lightly turbid foothill rivers with steady current, riffles over gravel and cobble, and lots of oxygen. They spend their days nosing along rocks and sand, grazing on the film that grows there.

Setting up their tank

Give them space and current. A single adult needs a big footprint; a group is really the way to go, and that means a 5- or 6-foot tank. Think 75-120 gallons for a small group.

• Flow and oxygen: Aim for brisk, river-like flow. Powerheads with sponge prefilters, a river-manifold setup, and lots of surface agitation. They sulk and go off food in sluggish water.
• Temperature: 64-72 F (18-22 C) is a sweet spot. Short swings are fine, but try to keep summer peaks under 75 F (24 C).
• Water chemistry: Neutral to slightly alkaline, moderate-hard water (pH 7.0-8.2; 6-15 dGH) works well.
• Substrate: Mix fine sand and rounded pea-to-small gravel. Add smooth cobbles for grazing. Avoid sharp edges that can tear their mouths.
• Scape: Build long riffles with rock piles and open lanes. They appreciate line-of-sight breaks. Plants are optional; tough rooted Vallisneria or potted swords can work, but they may be uprooted in strong flow.
• Lighting: Moderate. Let some algae grow on a few dedicated stones and the back glass for natural grazing.
• Filtration and maintenance: Big biofilter, heavy aeration, and 30-50% weekly water changes. Vacuum lightly so you do not strip all the biofilm they like to graze.

What to feed them

They are grazers first and foremost. Think periphyton, algae, diatoms, and a lot of fine organic bits. In a tank, they do well on a plant-heavy diet with some protein as a side dish, not the main course.

• Staples: Spirulina and algae wafers, high-fiber sinking pellets, and gel foods like Repashy Soilent Green or Super Green.
• Veggies: Blanched zucchini, cucumber, green beans, and spinach. Clip or skewer them so they do not blow around.
• Extras: Frozen daphnia, mysis, or bloodworms once or twice a week. Keep animal protein modest.
• DIY graze stones: Put a few cobbles in a bucket of tank water under a sunny window or an LED for a week, then rotate them into the tank for natural grazing.

How they behave and who they get along with

Peaceful, busy, and a bit skittish under bright lights. They work the bottom and mid-bottom zones, especially in the fastest parts of the tank. In a group of 4-6 they settle better and spend more time out in the open.

• Good tankmates: Fast, current-loving fish that ignore the bottom. Cool to temperate minnows and dace, rainbow shiners, or similar river fish do well. Keep sizes compatible.
• Use caution: Hillstream loaches and plecos compete for the same food. It can work in bigger tanks if you feed heavy and provide multiple graze zones.
• Avoid: Aggressive cichlids, large predators, fin-nippers, and slow fish that hate current.

Breeding tips

Spawning is doable but not simple. In the wild, suckers migrate into shallow, fast gravel in spring. You need that seasonal cue and the right structure.

• Seasonal cycle: Cool them to 55-60 F (13-16 C) for 6-8 weeks in winter, then raise gradually to 64-68 F (18-20 C) while increasing flow and photoperiod.
• Spawning site: A long riffle of clean pea-to-small gravel with strong current. Keep it debris-free so eggs can fall between stones.
• Group: One female with 2-3 males works. Males may develop small breeding tubercles and get more active.
• Egg care: No parental care. Use a mesh over the gravel or a slotted tray so eggs drop out of reach. High oxygen is non-negotiable.
• Raising fry: They are tiny. Start with green water, powdered spirulina, and infusoria, then move to freshly hatched brine shrimp. Keep flow gentle but well aerated in the fry tank.

Common problems to watch for

• Heat and low oxygen: Above mid-70s F they start breathing hard and go off food. Crank up aeration and cool the water.
• Mouth damage: Sharp gravel and rough rock can split their lips. Use smooth stones and rounded substrates.
• Starvation in clean tanks: If you polish the tank spotless, they run out of things to graze. Always keep a few algae stones cycling.
• Digestive issues: Diets heavy on bloodworms or high-protein pellets can cause bloat and long-term organ problems.
• Parasites: Wild-caught fish often carry flukes or nematodes. Quarantine 4-6 weeks and deworm if needed (praziquantel/levamisole as appropriate).
• Water quality swings: They eat and poop a lot. Ammonia spikes happen fast in new setups. Mature biofilter and big, regular water changes are your friends.